An FAG DTECT X1 online vibration monitoring system has prevented the failure of a steam turbine, which could have cost the Corus plant in Scunthorpe many thousands of pounds in lost power generation. The Central Power Station on the Corus site in Scunthorpe provides electricity for the site by utilising works arising gases.
There are a total of 6 steam turbines generating up to 53 MW of energy for the plant. The remaining required energy is drawn from the National Grid. It was only when Turbine No. 5 was taken off-line for routine maintenance that serious cracks in the generator’s retaining rings were discovered. The resident maintenance engineers immediately realised that the risk of a failure of this turbine would not only result in lengthy downtime and lost production, but in serious safety risks to plant personnel.
To ensure the continued safe operation of an identical generator, the maintenance team decided to act fast and conducted a HAZOP (Hazard & Operability Analysis) study on Turbine No. 4. If this sister unit was discovered to have the same problem as No. 5 Turbine, a more serious failure could have occurred. Following the study, a protective cover was put in place immediately, but it was clear that early failure detection was also required.
“We needed a quick response vibration monitoring unit to provide protection not only for the equipment but for our personnel,” says Maintenance Engineer, Josh Mortimer. “Having seen how successful the Corus PCM (Plant Condition Monitoring) Team had been at Teesside and in other areas of the Scunthorpe plant in preventing plant failures, I was keen to identify a system that was quick and easy to install and that was also easy for our operators to understand. The FAG DTECT X1 unit seemed ideal for our requirements,” he continued.
It was decided to install the DTECT X1 system on the exciter end bearing and the turbine end bearing of Turbine No. 4. Shortly afterwards the online vibration monitoring device detected a problem with one of the rotor blades. “Our attempts to protect this generator paid off,” says Chris Smith, Scunthorpe’s PCM Engineer. “By picking up the blade failure early on, we were able to prevent the failure of the whole turbine. In lost generation alone, this machine is worth £35,000 a day. Minimal damage and a quick return to service is obviously the preferred option.”
Wolfgang Hahn, Manufacturing Manager for the Central Power Station at Corus Scunthorpe confirms the company’s intention to continue the good work of the PCM department in recent years. “PCM has been working well for us. We get a good service from the PCM department and have saved the company a lot of money,” he confirms. “We are moving towards a full condition-based monitoring system as we recognise the considerable benefits to our plant. Energy prices remain high so it is in our own interests to reduce the need to draw from the National Grid by maintaining reliable equipment in our own plant. If we increase the reliability and availability of our equipment we can increase the power generated to the plant and reduce our costs significantly.”
This proactive approach to maintenance is welcomed by the Corus PCM Team. “The Central Power Station is always looking for ways to maximise the availability of its plant and equipment, and works very closely with our team to explore new ways of doing this, comments Ian Taylor, Business Development Engineer for PCM at Corus. “The FAG online monitoring systems have proved a cost-effective way of meeting their requirements, and it is refreshing to work with maintenance engineers who believe in what we are trying to do,” says Taylor.
The next three years will be challenging times for Scunthorpe, but with the support from Schaeffler to provide in-depth product training to their maintenance engineers and operators, they should be able to meet their maintenance objectives.
